Rendering nested lists

I have a problem with a site I've been working on - I have a list containing 4 Packages (custom type). The Package type has a Container part, and contains a number of PackageItems (another custom type).

I can successfully render the list and display a summary of the 4 packages - What I want to do is also display the details of the package items underneath each summary. I've tried a few ideas, but none have been successful.

To build a template of a child content item you'd need to call Services.ContentManager.BuildDisplay(item,"Summary").

I don't actually know if it's possible to call this directly from a view (will be experimenting with this later) - but all the existing examples show this being called either from a driver or a shape event/provider, and the results passed into the model
(which would therefore require custom code / module).

I'm just wondering, from the view, how did you get a reference to ContentManager? I was looking earlier and couldn't find it. (I have a specific case where I'd like to be able to customise the DisplayType from a template override)

But yes you probably want to do it from a driver or something else in the shape building pipeline if you want to avoid too much code in the view.